PBX communication system



FIG. 1 is a front view of a PBX communication system showing our new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a back view thereof; and,

FIG. 7 is a front, side and top perspective view thereof.

The broken lines throughout the views are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a PBX communication system, as shown and described. 